Characterizing the Human Body as a Monopole Antenna

This paper, for the first time, fully characterizes the human body as a monopole antenna in the frequency range of 10-110 MHz, which contains the resonance frequency of the human body. The human body is represented by an equivalent cylindrical monopole antenna grounded on a highly conductive ground plane that is analyzed based on the three-term approximation method. The reflection coefficient is measured using a human subject as a monopole antenna. Measurement results show that the theoretical predictions are in reasonable agreement. It is found that the human body resonates between 40 and 60 MHz depending on the posture of the body when it is fed by a 50-Ω impedance system at the base of the foot. A minimum reflection coefficient of -12 dB is measured which demonstrates that the human body can be potentially used as an antenna. Theoretically, it is predicted that the human body can be an efficient antenna with a maximum radiation efficiency reaching up to 70%, which is supported by measurement results found in the literature.